The present invention relates to a vehicular headlamp having a light distribution changing device that changes the distribution of light emitted from the headlamp by changing the direction of or selectively blocking light emitted from a light source.
A conventional vehicular headlamp includes a discharge bulb 12 forming the light source, a reflector 14 that reflects light emitted from the discharge bulb 12 to the front, a lamp body 16 that houses the reflector 14 and the discharge bulb 12, and a lens 18 that seals the front of the lamp body 16, as shown in the longitudinal sectional view of FIG. 4. Power is supplied to the discharge bulb 12 through a ballast circuit unit (discharge lamp lighting circuit) 20 so as to provide a continuously stabilized discharge current.
In addition, a discharge bulb type vehicular headlamp 10 includes a light distribution changing device for changing the distribution of output light so as to produce a high beam, a low beam, and the like. As the light distribution changing device, for example, a movable shade 24 may be employed, as shown in FIG. 4. In the present embodiment, a support stay 26 of the movable shade 24 is rotatably supported by a pin 30 fixed to a bracket 28 provided at the front surface of the reflector 14, and an output rod 34 of an actuator 32 installed behind the reflector 14 is pivotally attached to the support stay 26. A solenoid or a motor (not shown) is disposed inside the actuator 32. When the solenoid or the motor is operated, the output rod 34 advances or retreats accordingly. When the movable shade 24 is located at the position shown in FIG. 4, a low beam light distribution is obtained, and when the actuator 32 is operated to tilt the movable shade 24 forward, a high beam light distribution is obtained.
In the vehicular headlamp 10 including such a light distribution changing device, power is supplied to the discharge bulb 12 and the actuator 32 from a vehicle power source (not shown) through a power cord 40, two hookup cords 36A, 36B, a light source cord 38A, and an actuator cord 38B.
One end of the power cord 40 is connected to the vehicle power source, while the other end thereof is provided with a power connector 42. One end of each of the two hookup cords 36A, 36B is connected to a power receiving connector 44, which in turn is connected to the power connector 42. Power feeding connectors 46A, 46B are connected to the respective other ends of the two hookup cords 36A, 36B. One end of the light source cord 38A is provided with a light source side connector 48A connected to the power feeding connector 46A, and a socket 50 in which the discharge bulb 12 is mounted is connected to the other end thereof. The ballast circuit unit 20 is mounted on the lower inner surface of the lamp body 16 approximately in the middle thereof. One end of the actuator cord 38B is provided with an actuator side connector 48B connected to the power feeding connector 48B, and the actuator 32 is connected to the other end thereof. The connection of these connectors can be easily disconnected, such as when repairs or the like are required.
An opening is provided in the lamp body 16 and a bushing 56 is engaged with the opening. The hookup cords 36A, 36B pass through a through hole in the bushing 54. The bushing 56 provides waterproofing and dustproofing functions, in addition to preventing the hookup cords 36A, 36B from being worn as a result of a direct contact with the opening. The power receiving connector 44 of the hookup cords 36A, 36B is connected to the power connector 42 outside the lamp body 16, and each of the power feeding connectors 48A, 48B of the hookup cords 36A, 36B is connected to the light source side connector 48A and the actuator side connector 48B inside the lamp body 16. These connectors 42, 44, 46A, 46B, 48A, and 48B are firmly secured to the lamp body 16 or other desired component by fixtures (not shown) to prevent them from being disconnected due to vehicle vibration or the like.
However, in the conventional discharge bulb type vehicular headlamp 10, a relatively large number of parts, including the hookup cables 36A, 36B, the bushing 56, and the fixture for each connector is required between the power side connector 42, the light source side connector 48A, and the actuator side connector 48B, as described above. This presents problems in that the associated manufacturing requires much time and labor and the total cost is rather high.
To solve these problems, the present invention provides a vehicular headlamp in which a power connector is connected to a light source side connector and to an actuator side connector using the minimum number of parts, the lamp body can be made waterproof and dustproof, and each connector can be firmly secured to the lamp body.
More specifically, a vehicular headlamp according to the invention includes a light source, a reflector, a light distribution changing device that selectively changes the distribution of light by either changing the direction of or blocking the light emitted from the light source, an actuator that operates the light distribution changing device, a light source cord which is provided with a light source side connector at one end thereof and which is connected to the light source at the other end thereof, an actuator cord which is provided with an actuator side connector at one end thereof and which is connected to the actuator at the other end thereof are provided in a lamp body, and a hookup connector which is provided with a connection portion connected to a power connector provided in a power cord connected to a vehicle power source at one end thereof and a connection portion connected to the light source side connector and the actuator side connector at the other end thereof, wherein the hookup connector is connected to an opening provided in the lamp body with the other end thereof located inside the lamp body. With this arrangement, it is possible to make the lamp body waterproof and dustproof while reducing the number of parts, and to firmly secure each connector to the lamp body.
The light source may be a discharge bulb, and the light source cord may be provided with a ballast circuit unit in the central portion thereof. The use of a high efficiency discharge bulb can reduce power consumption.
The hookup connector can be connected to the opening by inserting the other end of the hookup connector in the opening and turning it. For this purpose, a flange is provided at a central portion of the hookup connector, and the flange covers a periphery of the opening when the hookup connector is connected to the opening. Accordingly, the hookup connector can be removably connected to the opening easily, and the lamp body can be made waterproof even more reliably.
The actuator may be installed at the lower side on the rear surface of a reflector, and the ballast circuit unit installed on the bottom portion of the lamp body. In this case the actuator and the ballast circuit unit are located close to each other, and accordingly a cord through which power is fed from the hookup connector to both parts can be made as short as possible.
The invention further provides a vehicular headlamp including a lamp body, a light source and a reflector mounted in the lamp body for emitting a light beam from the headlamp, means for changing the light distribution of the light beam and which is mounted in the lamp body, means for actuating the light distribution changing means, a single hookup connector mounted in an opening in the lamp body, first connection means for making electrical connections between the hookup connector and the light source and the light distribution changing means, and second connection means for making electrical connections between the hookup connector and the actuating means.
The light distribution means may be mounted on the lower front surface of the reflector, and the actuating means mounted on the rear surface of the reflector.
The light source may be a discharge bulb, in which case a ballast circuit unit is mounted on the inner lower surface of the lamp body.
The hookup connector preferably has a portion on the outer periphery thereof formed as a bayonet-type connection member for mounting the hookup connector in the aforementioned opening in the lamp body. The bayonet-type connection member includes a flange which covers the periphery of the opening when the hookup connector is connected to the opening. A packing maybe interposed between the flange and the opposed surface of the lamp body around the periphery of the opening.